This is a very interesting theoretical way to attain deep space travel and physicists discuss in the video:

The “Lightcraft” is a laser-propelled spacecraft concept that could ultimately run on other beamed energies, such as microwave.

You may recall some recent discussions at NASA about a microwave propelled thruster and the em drive.  This is somewhat related and actually came out 7 years ago.

Here is a related excerpt from wikipedia:

Beam-powered propulsion is a class of aircraft or spacecraft propulsion mechanisms that uses energy beamed to the spacecraft from a remote power plant to provide energy. Most designs are thermal rockets where the energy is provided by the beam, and is used to superheat propellant that then provides propulsion, although some obtain propulsion directly from light pressure acting on a light sail structure, and at low altitude heating air gives extra thrust.

The beam would typically either be a beam of microwaves or a laser. Lasers are subdivided into either pulsed or continuous beamed.

The rule of thumb that is usually quoted is that it takes a megawatt of power beamed to a vehicle per kg of payload while it is being accelerated to permit it to reach low earth orbit.^[1]

Other than launching to orbit, applications for moving around the world quickly have also been proposed.

Let’s check out the video of this concept on page 2

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